"More power," are the famous words
of comedian Tim Allen. It seems that Bob Carver has followed this
philosophy by taking the Sunfire power amplifier and upgrading
it. You can read the review of the original Sunfire by JEJ @ Here.
That amplifier came out 3 years ago. For a short time, Bob will
be literally pouring his heart and soul into the Signature version.
He hand-signs each one on the front (we've seen him do it) and
checks each one to ensure that it meets his standards.

From the cosmetics, you would not know that
the Sunfire Signature Amplifier is different from the Sunfire
Amplifier, except for the authentic John Hancock of one Bob Carver.
It has the candlelight yellow readout on the front that displays
how much power (Joules) is stored for the tracking downconverter.
The meter reads a little higher on the Sunfire Signature than
on the Sunfire, for obvious reasons.

The rear panel has numerous connectors.
First are the inputs which include Lab Direct, Normal (both unbalanced
RCA), and Balanced. The Lab Direct DC couples the input, and assumes
that your preamplifier does not have any DC offset. Normal and
Balanced have protection against DC offset. There are two sets
of outputs, Current Source and Voltage Source. The Current Source
outputs have higher output impedance (1 Ohm) in order to produce
a sound that is more like a tube power amplifier, while the Voltage
Source outputs are conventional low impedance outputs (0.01 Ohm)
like most solid state amplifiers.

Even just plugging the amp in, it is very
obvious that this is a bigger beast. The power supply stores more
energy, as the Joule Meter needle on the front is nearly pegged.
On the original Sunfire the needle is at about ¾. Just
as with the first model, I wish there were a power switch. Not
putting power on/off switches on hi-fi components is vogue these
days. It forces the user to leave the power on, which is better
for the component, both in sound quality (no warmup period) and
longevity of the parts (power surges at turn-on shorten their
lives). You can just leave it plugged in, and this way the amp
will always be warmed up and in its optimum state. Alternatively,
you can plug it in everytime you want to use it, or you can plug
it into a power strip that has an on/off switch. I usually left
it plugged in on the weekends and un-plugged it during the week
while I was at work. I'm more comfortable with this approach,
warmup period or not. I recommend getting your AC wall circuit
upgraded so that you have the amp plugged into at least 20 amps
of supply. This amplifier will use all the juice you can give
it, especially if you are using it to drive low impedance speakers.

At the heart of the Sunfire is the magical
tracking downconverter. Although downconverters themselves
are not new, this particular design is unique (patented) to the
Sunfire products. Without going into much detail, the tracking
downconverter stays 6 volts above the music signal at all times,
so it is very efficient, and the amplifier stays very cool even
at high volume (the output transistors only have to dissipate
6 volts x the current, which, even if it were 10 amperes, would
only be 60 watts). If you want to know more about this technology,
you can read it by clicking here.
Because the amplifier is so efficient with its use of the power
supply, the output doubles from 600 watts per channel at 8 Ohms
to 1,200 watts per channel when driving 4 Ohm loads, and 2,400
watts per channel into 2 Ohm loads. This will be dependent on
the availability of sufficient current from your AC wall outlet.

The inside of the chassis is packed with
the power supply . . . an excellent sign. An enormous toroidal
transformer occupies most of the space, along with two large power
supply capacitors. The output stages are on two PC boards, one
on each side of the chassis. Notice the absence of heat sinks.
This is due to the very efficient handling of power.

The Sunfire allows for several different
methods of hook-up. The normal operation is to use the voltage
source output, which is the standard amplifier output. The current
source output is recommended for electrostatic speakers. You can
also use a combination of the two by wiring your low frequency
drivers with the voltage source, and midrange and treble drivers
with the current source. I tried both of these configurations
and will elaborate more on them in a moment. There is also the
parallel mono option where you use a Y-connector with one preamplifier
output plugged into one leg of the Y-connector. The other two
legs of the Y are connected to the two amplifier inputs. One channel
output goes to the woofer, and the other channel feeds the midrange/tweeter.
Of course, you need two Signature amplifiers for this. There is
no bridging option.

During my listening sessions, I configured
the Signature in two different ways. The first was with the Sunfire Classic Vacuum Tube Preamplifier
being driven by the Meridian 508-24 CD player, and the Signature
driving a pair of speakers for two channel stereo. The second
method was in a home theater setup using the Signature amp to
drive my front left and right speakers. I used the Sunfire
Cinema Grand to power the other channels, with a Pioneer CLD-97
LD player and Sony S-7000 DVD player as sources. For speakers,
I utilized Monitor Audio and Mirage OM-6s. All cabling in both
situations was with Nordost Flatline.

Reviewing an amplifier is not always an
easy thing. Listening for what makes one amplifier sound better
or just different than another is a long subjective process. I
spent several nights enjoying the spacious sound of the Signature
amp.

Lorenna Mckennets Mummers Dance has the
Celtic feeling that truly comes to life. Other CDs that I used
for the listening tests included Rebecca Pigeon and Holly Cole.
"So and So" from Holly Coles "Dont
Smoke in Bed" is on of my favorites. Her voice flows with
such smoothness. The bass is right behind her, and the performance,
while not totally in my living room, comes close to being there.
I even threw in a little country, not something I normally listen
to, but Shania Twain's "Your Still the One" is such
a beautiful song. From Classic to Country or from Jazz to Rap,
everything sounds good when being driven by the Sunfire Signature.

Bob Carver has always done some cool things
with his products, and the current and voltage outputs are an
example. I liked the way the amp sounded when using the current
source output for the midrange and tweeters and using the voltage
source for the woofers. The top end sounded a bit more open, very
spacious if you will. It was easier on the ears. This configuration
is an option, not a requirement, but I am from the school that
says listen to what you like.

I mentioned earlier that I also put the
Signature into my home theater setup. To have three Signatures
on hand would have been a rush, but I was still able to get excited
with just one. The latest film from Wesley Snipes, "One Night
Stand" on DVD has a beautiful musical score to accompany
the film. There were several scenes when I was sure that I had
real musicians playing in my living room. The DTS version of Disneys
"Hunchback of Notre Dame" is a good demo of DTS and
a musical where the sound is as superb as the video quality. One
last film I watched and listened to, that really blew me away,
was "GI Jane". Riddly Scotts soundtrack was mixed
very well and can only truly be appreciated on a high quality
audio system, and the Sunfire Signature fits into this category
nicely. Of course, "bringing M-16 bullets to life" may
not be the socially acceptable way of using the dynamics of a
600 watt per channel amplifier.

At $2,995 the Sunfire Signature is a bargain.
Most amplifiers that are capable of this much power usually cost
at least 3 times the price. The Signature is only available for
a limited time, so I recommend searching out your local Sunfire
dealer and listening to one of these before it's too late.

Stacey L. Spears

&COPY; Copyright 1998 Secrets
of Home Theater & High Fidelity
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